Adsorption site blocker on H entry

As a conclusion, the promoting effects of adsorption site blockers on H entry can be understood not by considering the effective diminution of 0 the overall coverage of OPD H (determined by integration of adsorption pseudocapacitance vs. potential curves [117-119]), but by considering the variation of x the local OPD H coverage in the sites not blocked [obtained by normahzation of 0 or from the Tafel and permeation slopes (see Tables 1 and 2)]. If the surfece-bulk transfer step is in equilibrium, a significant increase of the bulk H eoncentration can be induced by ASB surface effects only for the HER mechanism where the steps of electroadsorption and chemical combination are coupled. This analysis provides a quantitative explanation of the effects of promotion of H absorption into iron and ferrous alloys. 

A.2 Predictions of the Effects of Adsorption Site Blockers on H Entry.141... 

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